Really logs provide understanding of this new formations and you will conditions from the subsurface, lined up mainly at the detection and comparison from possibly effective perspectives.
Dedication from saturation
Liquids saturation ‘s the small fraction of your pore level of the new tank stone which is full of h2o. It is generally presumed, until otherwise understood, your pore regularity perhaps not filled up with liquids is stuffed with hydrocarbons. Deciding liquids and you may hydrocarbon saturation is one of the earliest expectations out-of better logging.
Brush formations
All water saturation determinations off resistivity logs within the clean (nonshaly) structures that have homogeneous intergranular porosity depend on Archie’s liquid saturation formula, or distinctions thereof. [1] [2] The newest equation is
Getting convenience, new saturation exponent n is often drawn while the dos. Laboratory experiments show this is a fair worthy of having average circumstances. To get more exacting functions, electronic measurements towards cores tend to establish finest wide variety for n, a, and you may m. When key mentioned opinions is unavailable, the costs regarding a good and meters when you look at the Eq. 4 is projected the following: into the carbonates, F=1/? 2 is usually put; into the sands, F=0.62/? 2 [3] (Modest formula), otherwise F=0.81/? 2 (an easier setting practically comparable to this new Humble formula). These types of equations can be programmed into the spreadsheets and therefore are found in really log interpretation application.
The accuracy of the Archie equation, Eq. 1 and its derivatives, depends in large measure, of course, on the accuracy of the fundamental input parameters: Rw, F, and Rt. Continue reading F is normally obtained from the latest measured porosity of development through the matchmaking